Result card
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What are the incremental effects of population-based Abdominal Aorta Aneurysm Screening relative to no systematic screening?
Authors: Suvi Mäklin, Taru Haula, Kristian Lampe, Jaana Leipälä, Ulla Saalasti-Koskinen
Internal reviewers: Aurora Llanos-Mendez, Sergio Marquez, Urs Brügger, Mark Pletscher, Iñaki Imaz, Sonia García Pérez
Acknowledgments: Information Specialist Jaana Isojärvi (FINOHTA/THL, Finland)
The effectiveness of population-based AAA screening compared with no screening is reported in much more detail in the Effectiveness domain. This result card reports the incremental effectiveness based on the systematic literature review done in this domain, and on the basis of the decision-analytic modelling undertaken.
Literature review
Summaries of the incremental effects of screening obtained in previously published studies are provided in the literature review.
Modelling
The incremental effects of population-based AAA screening compared with no screening were also analysed using the decision-analytic model (see Domain Methodology), using the remaining expected lifetime of the screened population (in Finland) as the time horizon. The incremental effectiveness is reported in LYG. In the report of AAA screening in Finland {3} the life expectancy after elective AAA surgery was found to be similar to that of the control cohorts.
Systematic literature review
According to the current literature AAA is largely an asymptomatic disease prior to its rupture; the effects of AAA screening are seen primarily in the prolonged lifetime of the population. In all the 26 cost-effectiveness analyses included, a positive effect on the lifetime of the screened population was observed. Detailed data on the LYG was available in seven of the 26 studies {3, 10, 18, 24-27} and data on quality-adjusted life years (QALY) gained was also available from seven studies {18, 24, 26, 28-31}. The LYG ranged in the studies for men from 0.013 to 0.097 and for women from 0.011 to 0.02. The QALY gained ranged from 0.011 to 0.07 (reported for men only).
Three studies also included women as well {3, 32, 33}. One of them included only women and found a LYG of 0.02, which is also within the range of men’s results {32}. The authors concluded, however, that the results should be interpreted with some caution, because female-specific epidemiological data are scarce. Two other studies contained both men and women. The second oldest reviewed study concluded that screening should include both men and women {33}. The most recent study found a LYG of 0.011 for women and 0.027 for men, and concluded that AAA screening appears to be effective for both sexes but the estimate for women is less precise {3}.
Four systematic reviews on cost-effectiveness were identified, published between 2007 and 2010 and covering literature (at the latest) up to June 2008. Three of these reviews concluded that AAA screening increases the overall life expectancy of the screened population. One review was more critical, stating in its conclusions that most health economic evaluations have employed a number of optimistic assumptions in favour of AAA screening and that further analyses are needed {34}. This review also included other types of screening than population screening for AAA and hence its focus was somewhat different.
Detailed results are available as Appendix ECO-2. Included studies are summarised in more detail also in RC-ECO5.
Modelling
According to the base case analysis, the incremental effectiveness of population-based one-time ultrasound screening for 65-year-old men in Finland would be approximately 0.027 LYG compared with no screening (11.551 vs. 11.524 life years, respectively), using a 3% discount rate. For women, the incremental effectiveness would be smaller, 0.013 LYG (15.687 vs. 15.674 for screening and no screening, respectively). Without discounting the corresponding figures were 0.041 LYG for men and 0.022 LYG for women.
Systematic literature review
All 26 included studies found a positive impact overall of AAA screening on the life expectancy of the screened population. This increase ranged from 4 to 48 days for LYG and from 4 to 26 days for QALY gained. The figures are low in absolute numbers, since the total number of LYG is divided between all those invited to screening. The benefit is, however, experienced in a much more substantial manner in reality by those individuals who undergo a life-saving elective repair of AAA. For them the benefit may be counted in years – provided that the operation is successful. The impacts of screening in these studies are similar to those associated with other screening technologies.
We have cited above, in detail, mainly studies that reported upper and lower limits of the range of findings. Three key studies were not explicitly referenced but belong to the analysis {47–49}.
The systematic review within this domain focuses on economic analyses. Hence the literature on health effects may not be conclusive. Results within the clinical effectiveness domain should be consulted for a more inclusive view.
References
3. Mäklin S, Laukontaus S, Salenius J, Romsi P, Roth W, Laitinen R, et al. Vatsa-aortan aneurysman seulonta suomessa [screening for abdominal aortic aneurysms in Finland]. [Screening for abdominal aortic aneurysm in Finland] ed. Helsinki: Terveyden ja hyvinvoinnin laitos; 2011.
10. Thompson SG, Ashton HA, Gao L, Scott RA, Multicentre Aneurysm Screening Study Group. Screening men for abdominal aortic aneurysm: 10 year mortality and cost effectiveness results from the randomised multicentre aneurysm screening study. BMJ. 2009;338:b2307.
18. Henriksson M, Lundgren F. Decision-analytical model with lifetime estimation of costs and health outcomes for one-time screening for abdominal aortic aneurysm in 65-year-old men. Br J Surg. 2005 Aug;92(8):976-83.
24. Badger SA, Jones C, Murray A, Lau LL, Young IS. Implications of attendance patterns in northern ireland for abdominal aortic aneurysm screening. Eur J Vasc Endovasc Surg. 2011 Oct;42(4):434-9.
25. Spronk S, van Kempen BJ, Boll AP, Jorgensen JJ, Hunink MG, Kristiansen IS. Cost-effectiveness of screening for abdominal aortic aneurysm in the netherlands and norway. Br J Surg. 2011 Nov;98(11):1546-55.
26. Lindholt JS, Sorensen J, Sogaard R, Henneberg EW. Long-term benefit and cost-effectiveness analysis of screening for abdominal aortic aneurysms from a randomized controlled trial. Br J Surg. 2010 Jun;97(6):826-34.
27. Wanhainen A, Lundkvist J, Bergqvist D, Bjorck M. Cost-effectiveness of different screening strategies for abdominal aortic aneurysm. J Vasc Surg. 2005 May;41(5):741-51.
28. Giardina S, Pane B, Spinella G, Cafueri G, Corbo M, Brasseur P, et al. An economic evaluation of an abdominal aortic aneurysm screening program in italy. J Vasc Surg. 2011 Oct;54(4):938-46.
29. Montreuil B, Brophy J. Screening for abdominal aortic aneurysms in men: A Canadian perspective using monte carlo-based estimates. Can J Surg. 2008 Feb;51(1):23-34.
30. Henriksson M, Lundgren F, Carlsson P. Informing the efficient use of health care and health care research resources: The case of screening for abdominal aortic aneurysm in Sweden. Health Economics. 2006 30 Apr;15(12):1311-22.
31. Silverstein MD, Pitts SR, Chaikof EL, Ballard DJ. Abdominal aortic aneurysm (AAA): Cost-effectiveness of screening, surveillance of intermediate-sized AAA, and management of symptomatic AAA. Baylor Univ Med Cent Proc. 2005 Oct;18(4):345-67.
32. Wanhainen A, Lundkvist J, Bergqvist D, Bjorck M. Cost-effectiveness of screening women for abdominal aortic aneurysm. J Vasc Surg. 2006 May;43(5):908-14.
33. Russell JG. Is screening for abdominal aortic aneurysm worthwhile?. Clin Radiol. 1990 Mar;41(3):182-4.
34. Ehlers L, Sorensen J, Jensen LG, Bech M, Kjolby M. Is population screening for abdominal aortic aneurysm cost-effective?. BMC Cardiovasc Disord. 2008;8:32.
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